The present invention relates to method and apparatus for imaging skin, more particularly to method and apparatus for imaging ridge patterns on fingers and other areas of human skin without using conventional pigment-type ink.
For some time the human fingerprint has been recognized as a scientifically sound basis for identification which is unique to the individual. Fingerprinting is a proven valuable tool in law enforcement, government security and many other contexts wherein conclusive determination or establishment of a person's identity is of import.
The conventional methodology for ink fingerprinting involves first coating the ridged skin area of a finger with wet dark ink and then pressing the coated area upon a light surface, thereby leaving an impression which will eventually dry into a permanent image. Afterwards a cleansing agent for removing the ink from the affected skin areas is applied.
Most people who have been subjected to fingerprinting procedures which utilize ink will agree that such procedures are cumbersome and messy. Even when inadvertent ink soiling (e.g., of skin, clothing, documents, etc.) has been successfully avoided, such inking procedures offend many a person's sensibilities of neatness. Furthermore, once the fingerprint is formed the wet ink does not dry immediately and the fingerprint may therefore be vulnerable to smearing or smudging until it completely dries.
Messiness is a characteristic which has heretofore contributed to limiting the utilization of fingerprinting as an identification tool to more formal or specialized contexts. Reduction of messiness would open the door to more casual or prevalent utilization of fingerprinting.
For example, in many everyday situations a person's identity is verified by means of his or her signature in order that a business or organization may extend credit to that person. Signature verification, at best, is an inexact science which brings to bear the supposed perceptiveness of a handwriting "expert" who seeks to distinguish true signature matches from signature forgeries. Fingerprint verification, on the other hand, is not subject to such vagary and conjecture. A fingerprint cannot be forged. A fingerprinted signature (even a single fingerprint or thumbprint), unlike a handwritten signature, is foolproof and indisputable; it represents inalterable and inimitable physical characteristic, rather than alterable and imitable behavioral characteristic.
The need may also arise in some official capacities to perform fingerprinting "in the field." Governmental officials and agents, both military and civilian, such as police officers, investigators and casualty identification personnel, may experience the necessity or desirability of conveniently and facilely fingerprinting a person "on the spot" so as to avoid traveling to a designated fingerprinting station. Conventional ink fingerprinting systems, which implement, e.g., inkpads, cards and ink cleansers, do not readily lend themselves to on-site performance.
Various "inkless" fingerprinting methods which depart from conventional pigment-type ink fingerprinting have been disclosed, e.g., by Heinecke U.S. Pat. No. 2,082,735, Newkirt et al. U.S. Pat. No. 3,533,823, Meadows et al. U.S. Pat. No. 4,379,178 and Stanger et al. U.S. Pat. No. 5,249,370.